Quick iperf test on FreeBSD 10.1 running as a VM in ESXi 5.5

Take this with a grain of salt, as I really haven't done enough testing to state anything conclusive.

However, under ESXi 5.1u3, I was only able to get my iperf scores up to 2/3Gb/s, with the occasional 5Gb/s bust on my 10Gb/s network.

With ESXi 5.5u2 (patches as of today's date) I am able to get scores like this fairly consistently:

[  3]  0.0- 5.0 sec  5.70 GBytes  9.79 Gbits/sec

[  3]  5.0-10.0 sec  5.69 GBytes  9.77 Gbits/sec

[  3] 10.0-15.0 sec  5.69 GBytes  9.77 Gbits/sec

[  3] 15.0-20.0 sec  5.70 GBytes  9.80 Gbits/sec

[  3]  0.0-20.0 sec  22.8 GBytes  9.78 Gbits/sec

Not bad, not bad.

Even if the scores are not accurate, it's at least showing a dramatic improvement over my 5.1 configuration.

This is from a FreeBSD 10.1 VM under ESXi 5.5 to a bare-metal FreeBSD 10.1. VM-to-VM performance is a bit lower, but still quite good:

[ ID] Interval       Transfer     Bandwidth

[  3]  0.0- 5.0 sec  4.89 GBytes  8.41 Gbits/sec

[  3]  5.0-10.0 sec  5.46 GBytes  9.37 Gbits/sec

[  3] 10.0-15.0 sec  4.32 GBytes  7.42 Gbits/sec

[  3] 15.0-20.0 sec  4.87 GBytes  8.37 Gbits/sec

[  3]  0.0-20.0 sec  19.5 GBytes  8.39 Gbits/sec

The FreeBSD VM's are still vmx-08, and I'm using the built-in vmx driver in FreeBSD 10.1

This is also with the default configuration for sysctl values - I was planning on building a small script to check different tcp settings, but with speed like this, there are more pressing things to worry about.